<p>The electronic band structures of chemically modified antimonene (i.e., SbX, where X=CN or NC) were systematically studied using first-principles calculations based on density functional theory (DFT). Through the analysis of phonon dispersion and formation energy, we confirm that all chemically modified antimonene is energetically stable and thus can be synthesized experimentally in principle. Moreover, our calculation results show that the band structures of chemically modified antimonene are strongly dependent on the modification modes. Specifically, the semi-modified antimonene (Sb-SX) exhibits significant magnetism with half-metallic characteristics, while the fully-modified antimonene (Sb-FX) can be converted into a Dirac material. Owing to the presence of Dirac cones, the electronic properties of Sb-FX monolayers can be effectively modulated by applying external biaxial strain or an electric field. These findings provide new two-dimensional material candidates for developing next-generation electronic devices.</p>